In this report some electrodynamics problems of materials with negative refraction are considered. It is shown that for such materials many laws and equations must be recorded in a different way than in usual case, when index of refraction is positive. In the most of books and textbooks so-called nonmagnetic approach is used, which is valid for nonmagnetic materials (μ=1) only. This approach cannot be applied with respect to materials with negative index of refraction. It is shown that materials with simultaneously negative dielectric and magnetic permeabilities undoubtedly must possess the frequency dispersion. Correlation between phase and group velocities is pointed out for such materials. A question of so-called overcoming the diffraction limit by means of plates from material with negative refractive index is considered in details. It is shown that this effect is indeed reduced to a problem of matching between a source and a receiver of radiation. Such matching is possible due to propagation of the evanescent modes, for which the diffraction limit does not exist. These modes fade on distances of order of a wavelength, and only on such a distance it is possible to transfer picture details which are smaller than wavelength.

We report a true left-handed (LH) behavior in a composite metamaterial consisting of periodically arranged split ring resonator (SRR) and wire structures. The magnetic resonance of the SRR structure is demonstrated by comparing the transmission spectra of SRRs with that of closed SRRs. We confirmed experimentally that the effective plasma frequency of the LH material composed of SRRs and wires is lower than the plasma frequency of the wires. A well-defined left-handed transmission band with a peak value of -1.2 dB (−0.3 dB/cm) is obtained. We also report the transmission characteristics of a 2D composite metamaterial (CMM) structure in free space. At the frequencies where left-handed transmission takes place, we experimentally confirmed that the CMM structure has effective negative refractive index. Phase shift between consecutive numbers of layers of CMM is measured and phase velocity is shown to be negative at the relevant frequency range. Refractive index values obtained from the refraction experiments and the phase measurements are in good agreement. The experimental results agree extremely well with the theoretical calculations.

It seems to be feasible in the near future to exploit the properties of left-handed metamaterials in the telecom or even in the optical regime. Recently, split ring-resonators (SRR's) have been realized experimentally in the near infrared (NIR) and optical regime.^{1, 2} In this contribution we numerically investigate light propagation through an array of metallic SRR's in the NIR and optical regime and compare our results to experimental results. We find numerical solutions to the time-harmonic Maxwell's equations by using advanced finite-element-methods (FEM). The geometry of the problem is discretized with unstructured tetrahedral meshes. Higher order, vectorial elements (edge elements) are used as ansatz functions. Transparent boundary conditions (a modified PML method³) and periodic boundary conditions⁴ are implemented, which allow to treat light scattering problems off periodic structures. This simulation tool enables us to obtain transmission and reflection spectra of plane waves which are incident onto the SRR array under arbitrary angles of incidence, with arbitrary polarization, and with arbitrary wavelength-dependencies of the permittivity tensor. We compare the computed spectra to experimental results and investigate resonances of the system.

Some basic properties of nonradiating systems are considered. A simple connection is established between the existence of residual electromagnetic potentials and the current density spectrum of the system. The properties of specific configurations based on toroidal and supertoroidal currents are modeled with the finite-difference time-domain method. Possible applications are discussed. A design of a new type of nonradiating system, based on a left-handed metamaterial is proposed and the system performance is modeled numerically.

Negative refraction and left-handed electromagnetism in a photonic crystal are demonstrated in waveguide and free space experiments at microwave frequencies. Precision control to achieve tailor-made refractive indices has been achieved. The negative refraction in these photonic crystals is shown to lead to imaging by a flat lens. We have also developed a generalized theory of flat lens imaging. These results promise potential applications in a variety of optical and microwave systems for communications and imaging.

The dispersion equation of a magneto-inductive wave along a line of magnetically coupled resonant elements is investigated under conditions when retardation must be taken into account. It is shown that both the radiation resistance and the imaginary part of the mutual inductance appear in the modified dispersion equation which allows interaction up to the p^th neighbour. The problems arising in the solution of the full dispersion equation are discussed and it is concluded that the general solution leading to a large number of high-attenuation branches may not lead to a solution that is easily interpretable physically. It is suggested that the dispersion equation is to be derived from the variation of the current along an array of a finite number of elements excited by a voltage applied to the first element. The solution is obtained for a planar array of capacitively loaded loops in a closed form by inverting the complex mutual inductance matrix. It is shown that retardation and higher order interactions have greater effect upon the attenuation of the arising backward wave than upon the phase change per element. The appearance of a forward wave with a phase velocity close to that of light is also shown.

Multiferroics, i.e. the materials with electric and magnetic subsystems coexisting, are considered. The possible future application of materials in spintronics, storage devices and microwave technique are discussed. The results of the research devoted to the elaboration of new efficient multiferroics are presented.

One-dimensional lines of metamaterial elements supporting magneto-inductive waves are investigated for the case when elements' properties vary in a doubly periodic manner. It is shown that the dispersion of the magneto-inductive waves in this case demonstrates (analogously to acoustic waves in solids) an "optical" and an "acoustic" branch. The properties of the dispersion relation are investigated with attention paid to the width of pass- and stop-bands and the possibility of tailoring the dispersion properties within this approach is discussed.

Propagation of plane electromagnetic waves in 1D periodic structures including the layers with both positive and negative refraction indexes is considered within the frame of the long wavelength approximation. The dependencies of the media effective characteristics (dielectric, magnetic, gyrotropic, electrooptic) on the corresponding properties and the relative thicknesses of the layers are investigated. These dependencies can have a resonant form even at a fixed frequency of radiation and it causes a specificity of the interaction of electromagnetic waves with such composite materials. The detailed analysis of electromagnetic waves form is executed for the structure formed by optically isotropic layers that corresponds to an uniaxial magnetic effective medium. Some additional opportunities of controlling optical properties of the investigated structures caused by the presence of negative refraction layers are considered.

The optical properties of composite material made of metal nanospheres situated in the sites of three-dimensional lattice and embedded into dielectric matrix are considered. It is demonstrated that index of refraction of composite medium may acquire unit value at certain relations between dielectric constants. The method is developed for the description of optical properties of composite medium that takes into account retardation effects in nanospheres interactions. It is shown that obtained results coincide with Maxwell-Garnett theory in the limit of infinitesimal distances between nanospheres with respect to wavelength.

This paper proposes to apply nanoimprint and soft lithography to the manufacture of large area planar chiral photonic meta-materials. Both dielectric and metallic chiral structures in nanometre order were replicated by nanoimprint lithography (NIL). To carry out the NIL, a nanofabrication process for imprint templates with chiral features was developed. For the dielectric chiral structures, a single layer of thick hydrogen silsequioxane (HSQ) was used, and for metallic chiral ones a bi-layer PMMA/HSQ technique was employed. The polarization conversion capabilities of planar chiral structures (PCS) imprinted in dielectric materials have been experimentally observed. This indicates that the developed nanoimprint processes in this work have the prospect of manufacturing planar photonic meta-media in high volume at low cost. A hybrid lithography combing nanoimprint and soft lithography is proposed for the constructions of chiral cavities inside dielectric materials.

We will present the activities of METAMORPHOSE a network of excellence (NoE) formed under EU-FP6 on the area of metamaterials. The main scientific objective of the partners of this consortium is to develop new types of artificial materials, referred to below as metamaterials, with electromagnetic properties that cannot be found among natural materials. The results of this development should lead to a conceptually new range of radio, microwave, and optical technologies, based on revolutionary new materials made by large-scale assembly of some basic elements (nanoscopic and microscopic) in unprecedented combinations. Further information on this NoE can be found in http://www.metamaterials-eu.org.

A metal-in-dielectric metamaterial structure different from that composed of split-ring-resonators and wire units was proposed. The metamaterial layer is composed of randomly distributed parallel pairs of nanowires of subwavelength size that form electromagnetically active units. It was predicted that the metamaterial should exhibit macroscopic negative refraction. In a recent paper fabrication of the metamaterial in the form of periodic array of parallel golden nanorods with trapezoidal cross section was reported and a negative refractive index of n = -0.3 was observed at a wavelength 1.5 μm (200 THz). In this paper we simulate response of a single pair of nanowires to near-infrared illumination and observe surface plasmon resonances using FDTD method. We simulate light propagation through the metamaterial slab made of one, two and three layers. In each layer the nanowires cover 10% of the surface. In simulations made for a single layer medium, negative refraction is observed for wavelengths from 1.55 to 2.1 μm, with Δλ/λ ≈ 0.3. When the number of layers increases, the range of negatively refracted wavelengths becomes narrower. For a narrow range of wavelengths that are close to the resonant frequency the intensity transmission of three layers reaches −7dB for the angle of incidence of 10°. Then layers with two orientations of nanowires are considered. In the first stack of layers all nanowires are oriented in parallel. This configuration assures plasmon resonances for both the electric and magnetic components of electromagnetic wave in all layers. In the second stack, nanowires in two subsequent layers are oriented perpendicularly. In the second layer, the plasmon resonance for the electric component of light is due to the oblique incidence of light. For a small angle of incidence of a near infrared narrow Gaussian beam we calculate two characteristics: the attenuation vs. wavelength and the lateral shift of the beam on the plane-parallel slab vs. wavelength. For a narrow range of wavelengths simulations show negative refraction of a beam incident the plane of the nanowires and a corresponding shift in the far field.

This paper presents recent advances in the design and applications of metamaterials: Electromagnetic Band Gap, Artificial Magnetic Conductor and LH surfaces. Miniaturised EBG surfaces are studied and implemented using closely-coupled double-layer topologies. Antenna characteristics are shown from a multifrequency array (using non-uniform Left Handed (LH) superstrate), a planar base station antenna and a compact mobile handset prototype (incorporating a thin flexible miniaturised EBG surface). Frequency de-tuning, efficiency and radiation pattern results are presented.

We investigate generalized asymmetric left-handed (LH) slab waveguides that constitute an extension to the symmetric structure initially proposed by Pendry. By utilizing the asymmetry it has been shown that they have the potential for increased image resolution. This is due to the amplification of the formed surface waves (SWs) that is able to compensate material losses. Some preliminary studies in this direction have been reported in the literature but, to the best of our knowledge, there is no complete study of all possible SW eigenmodes supported by such LH waveguides. A rigorous theoretical investigation is presented herein that offers clear mathematical explanation and detailed physical insight into the formation of surface polaritons (SPs) in these heterostructures and provides the conditions for their existence. It is found that a rich variety of SP modes can exist (30 in total) that depend critically on the combination of the different refractive indices, constitutive parameters ε(ω) and µ(ω) the sample geometry. For each case we provide the geometric dispersion diagram and the profile of the corresponding stable field configuration from which the various characteristics of the mode (enhancement, phase reversal) are apparent. An interesting result of the above analysis is that, for certain choices of the material parameters, the coupling between the interfaces allows the existence of new 'supermodes' when no stable solutions exist at the isolated interfaces of the slab alone. Finally, the modes that give rise to negative group velocity are identified and key features of the dispersion diagrams are discussed, most of which are unique to the structures studied herein and have not been previously recovered with symmetrical studies.

A 5-fold enhancement in the luminescence of CdTe nanocrystal quantum dots (QDs) is observed when they are placed in proximity to a nanostructured Au film deposited by pulsed laser deposition technique. No enhancement is observed with a nanostructured Ag film. The enhancement is due to the interaction of the QDs excitons with the localized surface plasmons (LSP). The Au surface plasmon (SP) frequency is closer to the QDs emission frequency than Ag LSP frequency and this accounts for the differences in observed behavior. As the SP-QD interaction strongly depends on the geometric structure and shape of the metal nanoparticles, a comparison with QDs deposited on a film of Au colloidal nanoparticles is presented. In the case of QDs placed directly on the Au colloids the luminescence quenching is much stronger and with a spacer layer a 3.5-fold enhancement over the bare QDs luminescence is observed.

In this paper we examine properties of plasmon-polariton waveguide made of five rows of silver nanorods arranged in the hexagonal lattice. Electromagnetic wave illuminating metal structures generates surface plasmons. In nanoscale structures plasmons locally enhance near field and light propagates in modes confined below the diffraction limit. We present results of simulations using Finite Difference Time Domain (FDTD) method, which illustrate guiding visible light in the examined waveguide. We calculate modal properties of the waveguide. Propagation of two groups of modes with different symmetry with respect to the waveguide axis is observed. When the monochromatic light source is located on the waveguide axis both groups of modes are excited independently due to source symmetry. We assess that in the symmetric mode wavelengths longer than 500 nm are guided. For the antisymmetric mode that value is equal 450 nm. For off-axis illumination modes propagate together and form a snake-like beat pattern. Interference of modes from the first and second Brillouin zones (BZ) is also observed for a few wavelengths. To analyze the dispersion properties of the waveguide we assume Bloch type and absorbing boundary conditions in a single cell of the waveguide and make calculations on complex fields. FDTD equations work as a sieve that extracts modes with a given wavenumber from the initial field distribution. Then the guided frequency is found from spectrum. Group and phase velocities of modes are obtained from the dispersion relations.

The results are presented of spectral calculations of extinction cross-section for scattering of E- and H-polarized electromagnetic waves by cylinders made of Veselago material. The insolvency of previously developed models of scattering is demonstrated. It is shown that correct description of scattering requires separate consideration of both electric and magnetic subsystems.

Gold Split Ring Resonators (SRRs) were fabricated on silicon substrates by electron beam lithography and lift-off, with overall dimensions of approximately 200 nm. Reflectance spectra from the SRRs are similar to those published elsewhere. New devices are proposed based on the additional functionality afforded by the use of a silicon substrate.

Compact miniature microwave phase shifters have been designed on a combination of conventional (righthanded) transmission line sections and dual ones (left-handed) with negative dispersion. The phase shifters of two kinds are under consideration in this paper: an analog tuneable phase shifter using ferroelectric varactors as the tuneable components and digital phase shifters based on switched right-handed/left-handed transmission lines using p-i-n-diodes for switching the channels. All the devices have been implemented as multilayer integrated circuits. Operating the phase shifters in a wide frequency band is demonstrated. Solutions providing operation of tuneable ferroelectric phase shifter in a wide temperature range have been proposed.

We have conducted numerical and experimental studies of a simple metamaterial structure formed from 'C' shaped copper rings. Our study focuses on the investigation of the individual resonant elements by surface current and Q factor. We have also analysed wavelike signal propagation along these structures' axes recently predicted theoretically - so called magneto-inductive waves (MIWs). Computer based finite difference electromagnetic methods have been employed to both visualize the surface currents and investigate the effects of varying coupling within the structures. Experimental work has closely followed the theoretical work with measurements carried out using a Vector Network Analyzer to determine the frequency dependent scattering parameters. Applications of these structures are also considered in our work and the aim is to develop a robust, reliable design tool that enables rapid determination of the appropriate dimensions to enable operation of a magneto-inductive waveguide at a desired frequency. The simulation work demonstrates the possibilities for wave propagation in curved guides formed from stacks and rows of elements. And these may form the basis for a new class of microwave filter offering tunability and flexibility and requiring no direct connections to the driving circuits.

Nanowire composites are considered as a challenge in design and making of left-handed materials. We established several arrangements on silica glass substrate and show transmission measurements on fields of single nanowires. The results can be interpreted in such a way that the incident electromagnetic wave effectively couple to plasmon modes and lead to negative dielectric permittivity in a particular infrared spectrum. These effects depend on the structure, the topological and geometrical properties of the nanowires and their orientation relative to the wave. Transmission measurements with fields of parallel pairs of nanowires on both sides of the isolating show results that can be well interpreted as negative magnetic permeability and negative dielectric permittivity in the infrared spectra. This arrangement of nanowire pairs can act as a so- called left-handed metamaterial with a negative index of refraction in the infrared and visible spectral ranges.

We describe subwavelength properties of magnetic metamaterials designed to manipulate and control the near field by employing magnetoinductive (MI) waves. MI waves owe their existence to the magnetic coupling between metamaterial elements. Magnetic field distributions and Poynting vector streamlines are used to visualise the diamagnetic and paramagnetic properties of metamaterials and to analyse working principles of MI waveguides and MI waveguide components.

Left-handed materials have attracted growing attention in recent years. Although many efforts have been concentrated on the study of linear devices filled with left-handed materials, it was only recently that the nonlinear optical properties and optical response of such materials have been described. However, no analytical description of light propagation in these media has been proposed. In this communication, we develop an analytical model describing the interaction of coherent electromagnetic radiation in structures containing both right- and left-handed materials with a Kerr type nonlinearity. We study the paraxial propagation of electromagnetic radiation in such structures. Using a multiple time and space scales analysis, we derive a system of two coupled nonlinear Schrödinger equations for the amplitudes of the fields, allowing for both forward and reflected waves to be present in the structure. Diffraction, group velocity dispersion and Kerr nonlinear effects are taken into account. Appropriate boundary conditions are derived. Finally, we point out the differences between propagation in right- and left-handed materials.

In this paper, we review some of the key issues for designing, fabricating and assessing electromagnetic properties of left-handed propagation media, aimed at operating in the infrared region. We show how lefhandedness can be experimentally demonstrated and we address the important issue of loss. In the far infrared region, we consider in details the various stages in the study of a left handed transmission line with a direct evidence of backward propagation in the time domain. We also compared the respective advantages and drawbacks of dielectric based microstructures namely Photonics crystals and of metal nanotructures starting from shrunk split ring resonators.

Interest of using metal wire structures as transmission-lines in frequencies much higher than microwave region is recently arised. In this theoretical study guided waves in circular metal wire is investigated in infrared frequency range or even in optical region for transmission-line applications. In this frequency region the permittivity of the metal is not any more described by the conductivity of the metal but obeys the Drude model. The operational frequency region is between the electron scattering frequency and the plasma frequency. Just below the plasma frequency the permittivity is negative and almost a real number. The axial field components are written in terms of modified Bessel functions. The eigenvalue equation is evaluated for the guided modes by equating the continuity condition of the tangential field components at the interface of the free space and the wire region. The dispersion curves are calculated numerically and the propagation factors inside and outside of the wire region is illustrated as well as the propagation factor in axial direction. Also the field distribution in the cross-section of the structure is analysed. Analysing the properties of the propagating fields in metal wire, it is found that some modes are more and more tightly bound into the surface of the metal wire when the frequency approaces to the plasma resonant frequency. Using typical values for metals, the proper radius of the wire is in a range of about a hundred nanometers which is much below the wavelength of the guided mode even in optical region. The effect is analogous to that for guided fields in microwave frequency range for the circularly symmetric mode propagating in the metal wire surrounded by a thin dielectric layer. Now the similar effect is occured in subwavelenth region due to plasma phenomena. In this study it is demonstrated that subwavelength metal wire structures may have applications as transmission-line structures in infrared or optical region.

Recent advances in the field of left-handed materials (LHM) have renewed the interest for the study of the propagation properties in these materials. In particular, many works have been devoted to the study of the Veselago plate, which constitutes the simplest linear system based on LHM. Recently, Zharov and co-workers introduced a description of the nonlinear properties of LHM. In particular, they suggested that LHM could be used as the basis of power limiters, all optical switches, etc. In this communication, we consider a Fabry-Perot cavity filled with two materials having refractive indexes of opposite signs, and driven by an external coherent field. Using the well-known mean-field approximation, we derive a partial differential equation describing the bidirectional propagation of light in this optical cavity. In the absence of reflection at the interface between the LHM and the RHM, our model is similar to the well-known LL-model. However, an important difference that appears when considering LHM is that the sign of the diffraction term can be reversed by varying the geometry. Besides the bistable behaviour of the homogeneous response curve of the system, our study reveals the existence of modulational instability. The wavelength of the spatial dissipative structure emerging from that instability can be tuned continuously by varying the diffraction coefficient.

We study the out-of-plane photonic band structure of a two dimensional (2D) lattice with pillars made of left-handed material (LHM) or metal embedded in host dielectric. The band structures of 2D photonic crystals made of impedance-matched or impedance-unmatched LHM-RHM elements show resemblance to dielectric-dielectric and metal-dielectric structures, respectively. In particular, lossless LHM-RHM impedance-unmatched lattice supports lossless slow surface modes analogous to lossy modes at a metal-dielectric boundary.

Metal island films are widely-used as reflection layers in optics and optical data storage. Their optical properties are dominated by the effect of plasmon resonance and, thus, by size and shape of the metal islands. By altering size and shape of these islands, the optical properties of the metal films can be adjusted. Depending on the wavelength range and type of metal, the film reflectance can be either increased or decreased. It is shown that changes in size and shape can be caused by means of a laser. This allows a well-defined adjustment of the optical properties of thin metal films. The optical properties can be adjusted locally. This technique can be used in different fields such as holography, adaptive optics or multi-layer optical data storage.

The polymerization by focused laser light is a modern way how to create easily three-dimensional microstructures with even sub-micron details. We present how this method can be combined with non-classical laser beams to get a unique tool for generation of long and narrow polymer fiber.

Using the transfer matrix formalism and dynamical maps technique, we calculate numerically transmittance of polarized electromagnetic wave through aperiodic superlattices (generalized Fibonacci, generalized Thue-Morse, double-periodic and Rudin-Shapiro), built of left- and right-handed materials. In our calculations, strong dispersion of left-handed materials is taken into account, leading to tunnelling effects in a wide range of wavelengths and incidence angles. The results are presented in gray scale transmittance maps.